Semiconductor light emitting devices (e.g., light emitting diodes) that use nitride semiconductors are used in display devices, illumination, etc. Also, nitride semiconductors are utilized in high-speed electronic devices and power devices. When a nitride semiconductor layer is formed on a substrate having a different lattice constant or coefficient of thermal expansion, cracks and warp of the substrate occur easily. Technology is desirable for improving the performance, reducing the warp, suppressing the cracks, and realizing high productivity.